Birds of Northern Virginia - Documenting the Nature of Change (ASNV, 2006 - 60 page book) Based on 11 years of data collected by citizen scientists for the annual Northern Virginia Bird Survey, this book illustrates trends in a subset of bird species that breed in this region every year. Graphs for individual species show that some species, such as Brown-headed Cowbirds, appear to be increasing in numbers while others, like American Kestrels, are declining.